Evo Zig1

Galarian Linoone as well.

Evo Zig2

Evolving Galarian Zigzagoon into Galarian Linoone is easy, you just need to get it to level 20, but getting a Galarian Linoone to become an Obstagoon isn't quite as straightforward.

Evo Zig3

You're going to need to get it to level 35 at the very least, but that may not make it evolve, because this thing can only evolve into an Obstagoon at night. Simply level it up using a Rare Candy or any other method once the sun is well and truly down, and you'll have yourself a beautiful black and white Obstagoon at your command.